Various manipulations of a small specimen such as a cell are troublesome operations requiring delicate manipulation with a microtool. One example of such a manipulation is microinjection in a genetic transformation technology. In this genetic engineering technique, a host cell is pricked with an ultrathin glass tube so to introduce recombinant DNA. Introduction of recombinant DNA into a host cell using microinjection will next be described.
The host cell as a specimen is introduced to physiological saline in a petri dish. An operator (worker) uses suction to hold the host cell to the tip of a suction pipette, pricks a nucleus of the held host cell with an ultrathin glass tube, and introduces the recombinant DNA into the nucleus through the glass tube. While performing this operation, the operator uses a microscope to observe the procedure and ascertain that positions are correct.
However, because the host cell, which is in a natural orientation in the physiological saline, is suctioned and held without reorientation at the tip of the pipette by the above operation, when the nucleus is not on the side of the glass tube, in other words when the held specimen does not have a orientation suitable for manipulation, the operator must change the direction of the suction pipette to the specimen repeat the operation of suctioning and holding the specimen. Thus, the operator must take considerable time and trouble to obtain a desired orientation. Further, to capture a desired specimen by this manipulation, it is necessary to move the suction pipette closer to the specimen. In other words, this manipulation involves a great deal of effort requiring experience while observing under a microscope to obtain the desired orientation of a particular specimen.